Sleeve-type bearings (as distinct from the rolling anti-friction type bearings) for electric motors and other rotating equipment are presently designed and assembled in supporting end frames using one or the other of two basically different types of bearing structure mounting systems: (1) Cylindrical O.D. press-in bearings rigidly retained by their press-fit assembly into cylindrical sockets in the end frames; and (2) Spherical O.D. self-aligning bearings adaptively mounted between a spherical seat in the end frames and a spring or other retaining element which itself is pressed in or otherwise affixed in the end structure.
The presently-known self-aligning bearing systems, with their complex retainer and assembly features, are themselves more costly and space consuming than simply cylindrical press-in bearing systems. Under adverse design, assembly, operation or maintenance conditions, conventional spherical bearings may tend to rotate in their self-aligning sockets--or may even become displaced out of their sockets by impacts or uneven drive loads.
Notwithstanding their cost and other limitations, the spherical self-aligning systems are often used instead of the simpler cylindrical press-in bearings because of overall motor alignment and cost considerations. For example, assembly and operation of motors with rigid press-in bearings--and with the usually desired small shaft-bearing clearances, and without disruptive shaft-bearing misalignments--requires a high degree of precision and rigidity throughout the motor, including all structural intermediates between the bearings on each end of the shaft. The cost or practicality of maintaining this precision and rigidity often dictates the use of self-aligning bearing systems. Also, it should be noted that these current systems will readily and inherently accommodate total misalignments of 15 degrees to 30 degrees or more; whereas, for all practical purposes for motors or similar rotary equipment, 1 or 2 degrees, or at the most about 5 degrees, is all that is really required to fully accommodate the total of fabrication and assembly tolerance limits.
A basic purpose of this invention is to provide new self-aligning bearing mounting systems which, along with special advantageous fabrication and assembly means, provide self-aligning capabilities sufficient to accommodate the relatively few degrees of re-alignment needed in most motors and rotary-type equipment--and in the same bearing mounting system also provide the advantages of low cost, easy assembly, economy of space, retention security, and other features inherent in the simple cylindrical press-in bearings.